The man accused of fatally stabbing two passengers and wounding a third on a light-rail train in Portland, Oregon, has pleaded not guilty to charges included in a 15-count indictment.

Jeremy Christian shouted he was not guilty at Wednesday's arraignment, and added that he was defending himself against the aggression of surviving victim Micah Fletcher.

The judge did not ask him for a plea at the two-minute hearing, but court records filed later show not guilty pleas entered on his behalf.

He's charged with aggravated murder, attempted murder and other crimes.

Prosecutors say Christian stabbed the men after yelling hateful comments at two girls, one of whom was wearing an Islamic head covering.